GetExtension: vscode.typescript-language-features Not Found

[cemalgnlts]

Hi,
I am trying to get the typescript-language-features package with getExtension but it returns undefined.

console.log(api.extensions.allAcrossExtensionHosts);

// Result:
[
  { id: "vscode.css", ... },
  { id: "vscode.html", ... }
  { id: "vscode.typescript", ... },
  { id: "vscode.javascript", ... },
  { id: "vscode.typescript-language-features", ... },
];

const tsExtension = api.extensions.getExtension("vscode.typescript-language-features");
console.log(tsExtension); // undefined

[cemalgnlts]

Fixed:

- const tsExtension = api.extensions.getExtension("vscode.typescript-language-features");
+ const tsExtension = api.extensions.getExtension("vscode.typescript-language-features", true);

But I didn't get the result I expected. I tried to imitate this extension:
https://github.com/esm-dev/esm.sh/blob/main/packages/esm-vscode/src/extension.ts#L172

I got this error:

await tsExtension.activate(); // Cannot activate foreign extension.

[CGNonofr]

I think you are confusing VSCode extensions and typescript server plugins

[cemalgnlts]

Yes, you are right, the way I used it was wrong.

I found a log in the console:

Fetch API cannot load extension-file://jside.package-manager/node_modules/ts-pm-plugin/package.json.
URL scheme "extension-file" is not supported.

I then registered this JSON file.

// index.ts:
registerFileUrl("node_modules/ts-pm-plugin/package.json", new URL("./package.json", import.meta.url).href);

// package.json:
{
  "name": "ts-pm-plugin",
  "version": "0.0.1",
  "browser": "ts-pm-plugin.js"
}

And I found another log.

Fetch API cannot load extension-file://jside.package-manager/node_modules/ts-pm-plugin/ts-pm-plugin.js.
URL scheme "extension-file" is not supported.

And I registered this file:

// index.ts:
registerFileUrl("node_modules/ts-pm-plugin/ts-pm-plugin.js", new URL("./ts-pm-plugin.js", import.meta.url).href);

// ts-pm-plugin.js:
/** @param {{ typescript: import("typescript/lib/tsserverlibrary") }} modules */
function init(modules) {
  // eslint-disable-next-line @typescript-eslint/no-unused-vars
  const ts = modules.typescript;

  /** @param {ts.server.PluginCreateInfo} info */
  function create(info) {
    // Set up decorator object
    const proxy = Object.create(null);

    for (let k of Object.keys(info.languageService)) {
      const x = info.languageService[k];
      // @ts-expect-error - JS runtime trickery which is tricky to type tersely
      proxy[k] = (...args) => x.apply(info.languageService, args);
    }

    info.project.projectService.logger.info("Hello from TypeScript Server Plugin!");

    return proxy;
  }

  return { create };
}

// eslint-disable-next-line no-undef
module.exports = init;

Although it loads the plugin file, it does not call the init function.

[CGNonofr]

If it fails to load the script, I'm not surprised the function inside the script is not executed

Can you please provide a reproduction repo?

[cemalgnlts]

I started to prepare the sample repo and suddenly it occurred to me to enable TS Server Log like in the demo and examine the logs. I saw that the code gave an error in the logs, the module was not defined. After seeing this error, I converted it to ESM format:

- module.exports = init;
+ export default init;

Now my plugin is working thanks a lot.